I have seen it somewhere but can't find it anymore - there was a way how to load pages in a newsbox which had another plugins call included.
Right now I have a template with a couple of pages which have always one or two newsboxes connected by $news variable.
E.g.:
Page 1 > News01 + News02, Page 2 > News03 + News04, Page 3 > News05 + News06 + News07, etc.
News01 has a RegisterLoginForm
News02 has an AdvancedForm
Is such something possible at all? Or is there another News-like plugin to achive this? Or the only way is to make separate templates for any of such combined pages?

CMSimple.skIt's no shame to ask for an answer if all efforts failed.
But it's awful to ask without any effort to find the answer yourself.